OceanBase Database Enterprise Edition V4.2.1

V4.2.1 GA

Version information

• Release date: September 28, 2023
• Version: V4.2.1 GA
• RPM version: oceanbase-4.2.1.0-100000182023092722

Overview

OceanBase Database V4.2.1 is the first long-term support (LTS) version in the V4.2.x series. This version introduced new features compatible with MySQL, such as the VALUES statement and JSON_TABLE expression. It also provides compatibility with Oracle through features like DBLink for package calling and sequence reading. Additionally, this version introduced the Workload Repository (WR)-based data collection framework and enhanced end-to-end diagnostic capabilities for commercialization. It optimized system resource utilization and supports table-level restore and Tencent Cloud Object Storage (COS). This version is recommended in production environments for routine business operations both in the cloud and offline.

Key features

Compatibility with MySQL

• VALUES statement

  The VALUES statement was introduced in MySQL 8.0.19. It can be used to quickly construct a table of data or as a standalone DML statement with support for ORDER BY and Limit clauses. It can also be used as a special table in regular DML statements. OceanBase Database V4.2.1 is compatible with MySQL Database and supports the VALUES statement, making table value construction more convenient and easy to use. For more information, see VALUES.

• RENAME COLUMN

  The RENAME COLUMN syntax was supported since MySQL 8.0. It allows users to rename columns without changing their definitions, which is more lightweight than the CHANGE COLUMN syntax. OceanBase Database is compatible with the RENAME COLUMN syntax of MySQL 8.0 since V4.2.1. For more information, see RENAME COLUMN.

Compatibility with Oracle

• Extended DBLink capabilities

  In OceanBase Database V4.1.0, the Oracle mode already supported the ability to read and write native Oracle tables through DBLink. Starting from V4.2.1, it also supports reading remote packages through DBLink. After you establish a connection with Oracle Database, you can call remote stored procedures by using a string in the format of remote stored procedure name @DBLink name in the Oracle tenant of OceanBase Database. You can also call a stored procedure by using remote synonyms defined in the remote database or local synonyms defined in DBLink. For more information, see PL DBLink.

  In addition, OceanBase Database V4.2.1 supports access to remote SEQUENCE objects. Similar to data tables, you can access remote SEQUENCE objects, including calculating the NEXTVAL and CURRVAL values of SEQUENCE objects, by using a string in the format of SEQUENCE object name @DBLink name.

• Partition or subpartition renaming

  Oracle Database supports the RENAME PARTITION and RENAME SUBPARTITION syntax for renaming a partition or subpartition. OceanBase Database has supported partitioned and subpartitioned tables since its early versions but lacked a simple method to change partition names. Starting from V4.2.1, OceanBase Database is compatible with the RENAME PARTITION and RENAME SUBPARTITION syntax of Oracle Database, making it easier to rename partitions or subpartitions. For more information, see Rename a partition or subpartition.

OBKV features

• JSON_TABLE expression

  JSON is a semi-structured data format where users can extract specific values from JSON strings based on a path. The JSON_TABLE expression allows users to convert semi-structured data into structured data. The earlier versions of OceanBase Database already supported the JSON data type in both MySQL mode and Oracle mode, but the JSON_TABLE expression was not implemented in MySQL mode. To meet the needs of users who want to convert JSON data into structured data for computations, OceanBase Database V4.2.1 also supports this expression in MySQL mode. For more information, see JSON_TABLE.

• OBKV TTL

  Time-to-live (TTL) is a commonly used feature in NoSQL databases, designed to automatically expire data. For example, in businesses that deal with historical data, there is a need to periodically scan the data, determine its expiration time, and delete it accordingly. Many businesses currently rely on the TableAPI of OBKV. To simplify the management of periodic data, OceanBase Database provided the OBKV TTL capability since V4.2.1. Users can define TTL attributes at the table or row level using the CREATE TABLE statement so that expired data is not processed during read and write operations in OBKV.

Performance improvements

• Concurrent execution of CREATE TABLE

  In the earlier versions of OceanBase Database, DDL requests were executed serially in RootService queues. Starting from OceanBase Database V4.1.0, the concurrent DDL capability was introduced, with support for concurrent execution of TRUNCATE TABLE. To address the performance issues related to schema migration for tables with millions of data rows, V4.2.1 now supports concurrent execution of CREATE TABLE, providing a performance improvement of tenfold or even more compared with serial execution.

• Improved foreign key check performance

  Prior to OceanBase Database V4.2.1, foreign key checks were implemented using nested SQL statements, incurring significant overhead. From V4.2.1, foreign key checks are performed using Database Autonomy Service (DAS) tasks, and batch checks in single-table DML operations is supported. Additionally, with the check result caching strategy, noticeable performance improvements have been achieved in INSERT and UPDATE scenarios. In a single-node scenario (where the parent table and child table are on the same node), the performance degradation caused by foreign key checks during INSERT and UPDATE operations on foreign key tables is generally controlled to around 10% compared with tables without foreign keys. In a distributed scenario (where the parent table and child table are on different nodes), the performance degradation is generally controlled to around 30% compared with tables without foreign keys during INSERT and UPDATE operations.

• Dynamic sampling on MemTables

  OceanBase Database V4.2.0 introduced the dynamic sampling feature, which samples data during the generation of an execution plan. When the number of rows in the SSTable exceeds that in the MemTable, dynamic sampling is performed on SSTable blocks. When the number of rows in the MemTable exceeds that in the SSTable, dynamic sampling is performed on the MemTable. In V4.2.0, this was achieved through full read of the MemTable, which was relatively inefficient. However, in V4.2.1, direct sampling for the MemTable is implemented, utilizing RANGE partitioning to perform interval reads. This enhancement significantly improves the efficiency of dynamic sampling on the MemTable.

• Parallel read of archived logs

  In OceanBase Database V4.1.0, OceanBase Change Data Capture (CDC) can read archived logs through the CDC service or directly read logs from the archive destination. In V4.2.0, a network-based standby database reuses the log pulling framework of OceanBase CDC to pull logs from the primary database by using the CDC service. After the CDC service receives a log pulling remote procedure call (RPC) request from OceanBase CDC or a network-based standby database, the service first attempts to read logs from the local disk. If the corresponding logs do not exist in the local disk due to reasons such as log stream garbage collection (GC) or log recycling, and if the tenant has enabled log archiving, the CDC service reads logs from the log archive destination, such as the network file system (NFS) or Alibaba Cloud Object Storage Service (OSS). The log reading performance of the CDC service determines the log consumption speed at the downstream. If the performance of the CDC service in reading archived logs from OSS is poor, the synchronization link or the network-based standby database may lag behind the primary database and may be unable to become synchronized with the primary database. To address this issue, V4.2.1 allows the CDC service to read OSS-archived log files based on the basic capability of parallel read of OSS files.

Resource optimization

This version optimized the utilization of system resources in public cloud environments, including user tenant memory, memory of the SYS500 tenant, and operating system memory. For example, for Elastic Compute Service (ECS) instances with specifications of 128 GB or higher, the memory utilization of system resources has been reduced from around 30% to approximately 15%.

High availability enhancement

• Table-level restore

  Prior to OceanBase Database V4.2.1, tenant-level data restore was supported. If data within a table was damaged due to a misoperation, users needed to rely on the physical restore feature to restore the tenant to a previous point in time or use the import/export feature for table-level restore. V4.2.1 added support for table-level restore, allowing users to specify which backup data to use, which databases or tables to restore, which tenant to operate on, and the desired recovery point in time on the target cluster. For more information, see Table-level restore.

• Support for COS

  OceanBase Database V4.1.0 supports OSS as the backup media. OceanBase Database V4.2.1 supplements this support by allowing users to back up logs and data to COS and read backup data from COS for data restore.

Security enhancement

Data integrity protection: The Security Assessment of Commercial Cryptography Application imposes requirements for confidentiality and integrity protection on stored data in information systems. In the versions earlier than V4.2.1, the transparent encryption feature of OceanBase Database has already supported AES_ECD and SM4_CBC (which are named in the format of encryption algorithm_encryption mode), providing confidentiality protection for stored data. V4.2.1 added support for the GCM mode. In addition to data encryption, the checksum of ciphertext is calculated based on the key, and the ciphertext is checked during decryption to determine whether the ciphertext has been changed, thereby protecting data integrity.

Diagnostic capabilities improvement

• WR-based data collection framework

  The ease of use of the database performance diagnostics feature is closely related to the efficiency of system tuning. Oracle Database 10g introduces proactive automatic diagnostic capabilities such as Active Session History (ASH), Automatic Workload Repository (AWR), and Automatic Database Diagnostic Monitor (ADDM), and provides an inside-out (with information collected by internal components) and top-down (based on the database time and other metrics) database optimization and analysis framework. After decades of development, these capabilities have become industry benchmarks. OceanBase Database V4.2.1 implements a data collection framework similar to AWR of Oracle Database. The framework collects existing data such as ASH reports, statistics, wait events, and SQL execution details, and periodically persists performance-related views of OceanBase Database. OceanBase Database V4.2.1 introduces WR views and supports configuration adjustment and snapshot management by using DBMS_WORKLOAD_REPOSITORY packages. The new version also unifies, streamlines, enriches, and enhances SYSSTAT, ASH, and other statistical metrics for higher comprehensiveness and accuracy. The performance diagnostic capabilities will be further enhanced in future OceanBase Database versions. For more information, see Overview of WR.

• Enhanced ASH feature

  The ASH feature was introduced in OceanBase Database V4.0.0_CE. It samples the status of all active sessions in the system at an interval of 1 second and records the information in internal tables. In OceanBase Database V4.2.1, additional sampling points related to transactions, storage, and DAS were added. The ASH data is collected into the WR internal table at a default sampling rate of 10:1 and a collection interval of 1 hour. By analyzing ASH data, you can easily identify issues such as long wait events, slow SQL statements, and resource utilization of active sessions, which helps in performance optimization.

• End-to-end diagnostics feature

  OceanBase Database V4.2.0 supports visualized end-to-end tracing of SQL requests, and in V4.2.1, the configuration management capability for end-to-end diagnosis is further enhanced. A new view GV$OB_FLT_TRACE_CONFIG is added to record the configuration policies for end-to-end diagnostics at different levels. The GV$OB_PROCESSLIST view now includes LEVEL, SAMPLE_PERCENTAGE, and RECORD_POLICY columns to display the monitoring level, sampling frequency, and recording/printing policy that are effective for each session. Additionally, the GV$OB_SQL_AUDIT view includes a new column FLT_TRACE_ID to record the end-to-end trace information, enabling comprehensive SQL tracing. OceanBase Cloud Platform (OCP) will also provide corresponding page functionality to support this feature.

Product form

Public cloud primary address mode: In the public cloud architecture, the Client -> SLB -> ODP -> OceanBase Database link can be too long, resulting in significant performance loss in scenarios that require extremely high performance. For businesses whose data is stored on a single node and does not require read/write splitting, OceanBase Database V4.2.1 provides the primary address mode where a client can directly connect to a database through Alibaba Cloud Server Load Balancer (SLB), greatly reducing performance loss in the link.

Product behavioral changes

The following table describes the product behavioral changes made in this version.

View changes

The following table describes the changes to views made in this version.

Parameter changes

The following table describes the parameter changes made in this version.

Recommended versions of tools

The recommended platform tool versions for OceanBase Database V4.2.1 are described in the following table:

Upgrade notes

• An online upgrade of OceanBase Database Community Edition from V4.2.0 to V4.2.1 is supported.
• An online upgrade of OceanBase Database Community Edition from V4.1.0 to V4.2.1 is supported.
• We recommend that you upgrade OceanBase Database before you upgrade ODP.
• During the upgrade, the system automatically disables major compactions and DDL operations. After the upgrade is complete, the system resumes normal operation.
• An online upgrade of OceanBase Database Community Edition from V3.x to V4.2.1 is not supported.
• You can upgrade OceanBase Database Community Edition from V3.x to V4.2.1 through logical data migration by using OMS.